Battery comprising a flange formed at a peripheral edge and a protection circuit attached to the flange

ABSTRACT

A battery can  2  is composed of a can body  3  having a concave portion  31  for accommodating an electrode body  5 , and a metal cover  4  for sealing an opening end of the concave portion  31  of the can body  3 . The can body  3  is formed in a plate shape by subjecting a metal plate to shallow drawing. A flange  32  is provided at a peripheral edge portion of the opening end of the can body  3 , which is bonded to be integrated with the metal cover  4  to keep an air-tight and liquid-tight state in the concave portion  31.

TECHNICAL FIELD

The present invention relates to a battery suitable for use as a powersource of small electronic equipment such as portable electronicequipment, and in particular, to a configuration of a thin battery.

BACKGROUND ART

Batteries used as power sources of electronic equipment have, forexample, a cylindrical shape or a prismatic shape. In a cylindricalbattery, a metal can deep-drawn to a cylindrical shape (cylindricaldrawing) is used, and in a prismatic battery, a metal can deep-drawn toa prismatic shape (prismatic drawing) is used.

On the other hand, in small portable electronic equipment such as aportable information terminal requiring thinness, a relatively thinbattery is used. This kind of thin battery is classified into thefollowing types.

(1) A thin battery in which a metal can (deep-drawn can) subjected tothe above-mentioned deep-drawing is used, and a metal cover is fitted toan opening of the metal can, followed by welding (e.g., see aconventional prismatic non-aqueous electrolyte secondary batterydescribed in JP 11(1999)-185820 A).

(2) A thin battery using a laminate, in which a metal foil such as analuminum foil and resin are stacked, as an outer member so as to set theentire thickness small.

(3) A thin battery in which a metal can (shallow-drawn can) subjected toshallow-drawing, such as a lunch box, is used, and a metal cover isfitted to an opening of the metal can, followed by welding (e.g., see anon-aqueous electrolyte solution secondary battery described in JP11(1999)-185820 A).

In recent years, as seen from the spread of the above-mentioned portableinformation terminal, there is a strong demand for small andlight-weight electronic equipment. Along with this, there also is anincreasing demand for thinness of a battery to be mounted on theelectronic equipment.

However, a conventional thin battery has a prismatic shape or anelliptically cylindrical shape. Therefore, in order to attach such abattery to equipment or a resin pack (battery pack) to be mounted on theequipment, it is necessary to provide a battery chamber or fix thebattery at a predetermined position with a double-faced tape or anadhesive. When the battery chamber is provided, the thickness of theequipment is increased by the thickness of the battery chamber. When thebattery is fixed with an adhesive, an increase in thickness of theequipment can be avoided; however, it is difficult to separate thebattery for disposal, which is likely to have detrimental effects inmodern time as recycling is important.

Furthermore, the conventional thin battery configuration as described inthe above (1) to (3) cannot sufficiently meet the demand for furtherthinness. Alternatively, even if a battery can be made thinner, itsstrength may not be sufficient, inconvenience is likely to occur in thecourse of production, it is not easy to set the battery on equipment,etc. Thus, various problems occur.

More specifically, in the battery described in the above (1), adeep-drawn can is used as a battery can, so that there is apredetermined limit to the size to be formed. For example, the thinnestcan has a thickness of about 3 mm, and it is impossible or verydifficult to obtain a can with a thickness of about 3 mm or less by thecurrent deep-drawing technique. Therefore, in order to obtain such athin battery can, a stacked material such as a laminate as describedabove cannot help being used as a battery outer member. In this case,although the thinness of the laminate can be ensured, the strength ofthe laminate with respect to sticking and bending is smaller than thatof a metal can, and furthermore, there is a possibility of swelling of abattery and leakage of liquid.

Furthermore, even if a metal can with a thickness of 3 mm or less can beformed, a deep-drawn can has the following problems.

(A) As the thickness of a metal can is decreased, the width of anopening thereof (opening width in a thickness direction of the can) isdecreased, whereby it becomes difficult to insert an electrode in themetal can.

(B) Terminals are attached to attachment holes provided at a metal coverfor sealing an opening of a can, via an insulating packing (gasket) madeof resin. When the width of the opening becomes narrow, the insulatingpacking is placed doser to an opening edge. Therefore, when the metalcover is fitted to the opening and bonded thereto by laser welding orthe like, the insulating packing is likely to be melted due to weldingheat between the metal cover and the can.

(C) For deep-drawing, only an extendable material having a requiredextensibility is used. Therefore, the kind of metal to be formed islimited, and the hardness of metal to be formed is small. Therefore, adeep-drawn can is weak to the swelling of a battery. Thus, materialsthat have a large hardness (i.e., that are hard), light weight andstrength cannot be used even if desired.

On the other hand, a battery using a shallow-drawn can described in theabove (3), more specifically, a battery as described in, for example, JP11(1999)-185820 A can avoid most of the above-mentioned problems in thebattery using a deep-drawn can. However, such a battery also has thefollowing problems.

(a) For example, a peripheral edge of the maximum opening of a can isprovided with a cover having the same size as that of the peripheraledge, and the vicinity of the peripheral edge of the maximum opening iswelded. Therefore, welding heat is likely to be transmitted to anelectrode body (electrode element) in a can and components placed nearthe welded portion, which may have thermal influence.

(b) In the case where a cover is attached by crimping an outer peripheryof the cover and the peripheral edge of an opening (i.e., by seaming),instead of welding, productivity is decreased compared with the caseusing welding, and there may be a possibility of leakage of liquid fromthe connected portion between the outer periphery of the cover and theperipheral edge of the opening.

(c) A battery has a simple prismatic shape although it is thin.Therefore, in order to provide a protection circuit required in asecondary battery, it is necessary to separately keep or provide a spacefor the protection circuit or a base for attachment thereof.

(d) It is necessary to provide a battery chamber for attaching a batteryto equipment or a resin pack (battery pack) or to fix a battery at apredetermined position with a double-faced tape or an adhesive. Thus,there are problems similar to those in the case of a prismatic orcylindrical thin battery as described above.

SUMMARY OF THE INVENTION

Embodiments of the present invention provide a battery with a novelconfiguration that can solve the above-mentioned possible problems interms of a shape, attachment, strength, productivity, and the like inthinning of a battery.

One embodiment of the present invention relates to a battery including acan body having a concave portion for accommodating an electrode bodyand a metal cover for sealing the opening end of the concave portion ofthe can body, which is composed as follows. The can body constituting abattery can has a plate shape formed by subjecting a metal plate toshallow drawing, and a peripheral edge of the opening end of the canbody is provided with a flange capable of keeping the inside of theconcave portion of the can body in an air-tight and liquid-tight stateby being bonded to be integrated with the metal cover. In the concaveportion of the can body, an electrode body in which a positive electrodeand a negative electrode are stacked with a separator interposedtherebetween and an electrolyte solution are accommodated, and the metalcover is bonded to be integrated with the flange of the can body underthis condition, whereby the opening end of the concave portion of thecan body is sealed.

As means for bonding the can body so as to be integrated with the metalcover, there is a method for bonding the metal cover to the flangeportion of the can body by adhesion with resin or laser welding.However, considering various kinds of factors such as productivity orcost, adhesion with resin is desirable.

Examples of the material constituting the can body and the metal caninclude an iron plate, a nickel plate, an aluminum plate, an alloy platethereof (i.e., an iron alloy plate, a nickel alloy plate, an aluminumalloy plate, an iron-nickel alloy plate, an iron-aluminum alloy plate, anickel-aluminum alloy plate), a magnesium alloy plate, a stainless steelplate, a rolled steel plate plated with nickel, and a stainless steelplate plated with nickel. These metal plates may be used alone or incombination. In the case of placing importance on strength and lightweight, it is preferable to use a metal plate made of an aluminum alloyhaving Hv (Vickers hardness) of 70 or more, which has high strength andlight weight, and a metal plate made of a magnesium alloy. Furthermore,in the case of placing importance on resistance to corrosion withrespect to an electrolyte solution, it is preferable to use a rolledsteel plate or a stainless steel plate plated with nickel. Furthermore,regarding the metal cover, the same material as that of the can body isused on the bonded surface side with respect to the can body, and a cladmaterial (for example, nickel clad material obtained by stacking nickel)that is a stacked material excellent in strength and lightness can beused on the opposite side surface.

In order to suppress the expansion of the electrode body and theswelling of the battery can in the thickness direction due to anincrease in an internal pressure of the battery, it is desirable thatthe metal cover and one surface (bottom surface) of the can body placedso as to be opposed to the metal cover are formed respectively in aconvex shape toward an inside of the battery, and a deformation amountin a projection direction at a center of the convex shape is 0.05 to 0.3mm. When the projection amount is smaller than this, the effect ofpreventing the swelling of the battery can is poor. When the projectionamount is larger than this, the electrode body is pressed more thannecessary, and the capacity of the can is decreased, which is notpreferable. Furthermore, in order to exactly suppress or prevent theswelling, it is preferable that a range corresponding to an area of theelectrode body to be placed inside is formed in a convex shape.

A part of the can body or a part of the metal cover opposed to the canbody may be provided with a cut-in portion formed by press forming, andthis portion can be defined as a safety valve that releases an internalpressure of the battery to outside when the internal pressure of thebattery increases to a predetermined value or more.

In order to form a base portion or the like for providing a protectioncircuit in the battery of the present invention, it is desirable that apart of the flange of the can body is formed as a wide flange portion,and its width is set to be larger than that of the remaining flangeportion. In other words, it is desirable that the flange is formed onthe periphery of the battery can, and the flange width of a part thereofis larger than that of the remaining portion. In this case, how much thewidth of the wide flange portion is set to be larger than that of theother flange portion is determined in view of the size of the entirebattery, the size of the protection circuit, and the like. Generally,the wide portion is set to be 1 mm to 6 mm.

In order to electrically connect the output terminals of a positiveelectrode and/or a negative electrode to the protection circuit at ashortest distance and simplify the wiring therebetween, the wide flangeportion can be provided with output terminals of a positive electrodeand/or a negative electrode. Furthermore, the following also ispossible: among circumferential surface portions in a thicknessdirection of the can body (forming side surfaces of the concaveportion), a circumferential surface portion on a side where the wideflange portion is positioned is provided with a lead portion of one ofthe output terminals of a positive electrode or a negative electrode,and the wide flange portion is provided with the other output terminal.

In order to make it unnecessary to separately keep a space and a basefor attaching the protection circuit, and facilitate an operation ofattaching the protection circuit for fixing, in other words, in order toeasily obtain a thin battery provided with a protection circuit, aprotection circuit can be attached to the wide flange portion. In thiscase, the configuration of attaching a protection circuit may be, forexample, as follows.

The protection circuit is incorporated to be modulized in a substrateprovided with a plurality of elastic chips having engagement hooks atends, at predetermined positions on an outer peripheral portion. On theother hand, a peripheral edge of the wide flange portion is providedwith a rising portion in a substantially U-shape in a plan view havingengagement holes at predetermined positions, formed so as to be bent ina thickness direction of the can body. The engagement hooks of theelastic chips in the protection circuit module are engaged with theengagement holes in the rising portion, whereby the protection circuitmodule is fixed to the wide flange portion.

The protection circuit is incorporated to-be modulized in a resinmolding provided with a pair of elastic chips having hooks at ends, atboth side portions, and having grooves in which the wide flange portionis fitted slidably on inner surface sides of the side portions. On theother hand, both the side portions of the wide flange portion areprovided with cut-away portions at predetermined positions. When boththe side portions of the wide flange portion are fitted in the groovesin the protection circuit module to slide to a predetermined position,the hooks in the protection circuit module are engaged with the cut-awayportions in the wide flange portion.

The protection circuit is attached to the wide flange portion and anoutside thereof is covered with a metal (e.g., aluminum) case, and underthis condition, the metal case is welded to the wide flange portion.

According to one embodiment of the present invention, the can body is aplate-shaped shallow-drawn can, and a peripheral edge of the opening endof the can body is provided with a flange capable of keeping the insideof the concave portion of the can body in an air-tight and liquid-tightstate by being bonded to be integrated with the metal cover. Therefore,as means for facilitating the attachment/detachment operation toequipment, the flange can be used. For example, if a guide portioncorresponding to the flange of the battery can is formed at a portion ofthe equipment where the battery is to be attached, merely by insertingthe flange to the guide portion so as to allow it to slide, the batterycan be attached/detached with respect to the equipment. Thus, a batterycan be realized, which is excellent in attachment to the equipment andcan be easily separated from the equipment for disposal after use.

The metal cover is bonded to the can body at the flange provided on theperipheral edge of the opening end of the can body. Therefore, the metalcover can be easily attached (e.g., thermal adhesion) to this portionvia resin, and a battery can be produced at lower cost compared with awelding method. Furthermore, even in the case of performing laserwelding instead of adhesion with resin, the other component materialsare isolated to positions relatively away from the welded portion.Therefore, thermal influence on various kinds of components constitutingthe battery, such as an insulating packing, an electrode, a separator,and the like can be avoided.

According to one embodiment of the present invention, a plate-shaped canbody obtained by shallow drawing is used, so that the battery can with athickness of 3 mm or less can be formed relatively easily. In this case,there is no constraint in terms of materials as in the case of using adeep-drawn can. Therefore, materials having required characteristics canbe selected relatively freely from various materials. Thus, a thinbattery that can sufficiently withstand sticking, bending, swelling, andthe like (in other words, that is excellent in resistance to sticking,resistance to bending, resistance to swelling, and the like) can berelatively easily obtained, although the entire thickness is 3 mm orless.

Furthermore, in the case where the metal cover and one surface (bottomsurface) of the can body placed so as to be opposed to the metal covercan are formed respectively in a convex shape toward an inside of thebattery, and a deformation amount in a projection direction at a centerof the convex shape is 0.05 to 0.3 mm, the expansion of the electrodebody and the swelling of the battery can in the thickness direction dueto an increase in the internal pressure of the battery can besuppressed.

If a part of the can body or a part of the metal cover opposed to thecan body is provided with a cut-in portion formed by press forming as asafety valve, this cut-in portion is broken when the internal pressureof the battery increases to a predetermined value or more, and theinternal pressure of the battery is released outside from this portion.

In the case where a part of the flange of the can body is formed as awide flange portion having a larger width than that of the remainingflange portion, in other words, in the case where a part of the flangeprovided on the periphery of the battery can is formed as a wide flangeportion, the protection circuit can be attached to the wide flangeportion. Thus, in the case of providing the protection circuit, it isnot necessary to separately keep a space and a base portion therefor. Inthis case, if one or more of the configurations recited above isadopted, the output terminal can be electrically connected to theprotection circuit at a shortest distance, so that wiring therebetweencan be simplified.

According to one or more configurations, merely by fitting theprotection circuit module in the rising portion provided at the wideflange portion, and engaging the engagement hooks provided at theelastic chips of the protection circuit module with the engagement holesin the rising portion, the protection circuit can be easily fixed to thewide flange portion. Furthermore, according to one or moreconfigurations, both side portions of the wide flange portion areinserted in the grooves provided on inner surfaces of both side portionsof the protection circuit module so as to allow the wide flange portionto slide, and the hooks of the elastic chips provided at both sideportions of the protection circuit module are engaged with the cut-awayportions at both side portions of the wide flange portion, whereby theprotection circuit can be easily fixed to the wide flange portion.

In addition, according to one or more configurations, the protectioncircuit is modulized. According to one or more configurations, theprotection circuit attached to the wide flange portion is covered with ametal case. Because of this, the protection circuit is not exposedoutside in either case. Thus, the protection circuit can be preventedfrom being damaged and dust can be prevented from adhering to theprotection circuit.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is an external perspective view showing a battery of the presentinvention.

FIG. 2 is a plan view of a battery.

FIG. 3 is a cross-sectional view taken along a line III-III in FIG. 2.

FIG. 4 is a cross-sectional view taken along a line IV-IV in FIG. 2 anda partial enlarged view thereof

FIG. 5 is a perspective view of the periphery of a flange in a battery,showing an exemplary state in which a protection circuit is provided tothe flange.

FIG. 6 is an enlarged cross-sectional view taken along a line VI-VI inFIG.5.

FIG. 7 is a perspective view of the periphery of a wide flange portion(first flange portion) in a battery, showing another example in which aprotection circuit is attached to the flange portion.

FIG. 8 is a perspective view of the periphery of a wide flange portionin a battery, showing a still another example in which a protectioncircuit is attached to the flange portion.

FIG. 9 is a perspective view of a configuration of the periphery of awide flange portion in a battery and a protection circuit module,showing an example in which the protection circuit module is attached tothe flange portion.

FIG. 10 is a cross-sectional view showing a state in which theprotection circuit module is attached to the wide flange portion in thebattery shown in FIG. 9.

FIG. 11 is a perspective view of a configuration of the periphery of awide flange portion in a battery and a protection circuit module,showing another example in which the protection circuit module isattached to the flange portion.

FIG. 12 is a cross-sectional view showing a state in which theprotection circuit module is attached to the wide flange portion in thebattery shown in FIG. 11.

FIG. 13 is a perspective view of the periphery of a wide flange portionshowing an example in which a protection circuit is attached to a wideflange portion in a battery and the protection circuit is covered with acase made of metal (aluminum).

FIG. 14 is a cross-sectional view showing a state in which theprotection circuit module shown in FIG. 13 covered with a metal case iswelded to a wide flange portion.

FIG. 15 is a perspective view showing an example in which a battery witha protection circuit module is inserted between a pair of contactsprovided at external equipment so that the contacts are electricallyconnected to each other.

DETAILED DESCRIPTION OF THE INVENTION

FIGS. 1 to 6 show an example in which one embodiment of the presentinvention is applied to a prismatic lithium ion secondary battery(hereinafter, referred to as a “battery”). As shown in FIGS. 1 and 2, abattery 1 has a battery can 2 that has a prismatic shape in a plan view(state in FIG. 2) provided with four rounded corners. As shown in FIGS.1 to 4, the battery can 2 is composed of a can body 3 having a concaveportion 31, and a metal cover 4 for sealing an opening end of theconcave portion 31 of the can body 3.

The can body 3 is formed in a plate shape by subjecting one metal plate(sheet plate) to shallow drawing, and a flat flange 32 is formed alongan entire periphery of a peripheral edge of the opening end. In theflange 32, a width (flange width) L1 of a flange portion (first flangeportion) 32 a at a first short side portion 3 a positioned on a upperend side of the can body 3 in the state shown in FIG. 2 is larger by 1mm or more than a width (flange width) L2 of a flange portion (secondflange portion) 32 b at each long side portion 3 c positioned on bothsides of the can body. In the illustrated example, the first flangeportion 32 a corresponds to a wide flange portion in the presentinvention, and L1=2.5 mm and L2=1.5 mm.

As shown in FIGS. 3 and 4, an electrode body 5 and an electrolytesolution (not shown) (e.g., non-aqueous electrolyte solution obtained bydissolving an electrolyte such as LiBF₄ in a non-aqueous solvent such aspropylene carbonate and ethylene carbonate) and the like are containedin the concave portion 31 of the can body 3 (i.e., in the battery can2). The electrode body 5 is formed by winding a sheet-shaped positiveelectrode containing, for example, LiCoO₂ as an active material and asheet-shaped negative electrode containing, for example, graphite as anactive material in a spiral shape with a separator placed therebetween,and deforming by crushing the entire body to an elliptical shape incross-section in accordance with a cross-sectional shape of the concaveportion 31 so that the entire body is accommodated in the concaveportion 31 of the can body 3. Conducting tabs (only a conducting tab 6on the negative electrode side is shown in an illustrated example) areled respectively from the sheet-shaped positive and negative electrodesconstituting the electrode body 5. The conducting tab (not shown) on thepositive electrode side is connected to a predetermined position of aninner surface of the can body 3, and the conducting tab 6 on thenegative electrode side is connected to the negative electrode terminal7 (described later).

At a predetermined position of a circumferential surface portion(hereinafter, referred to as an “upper wall portion”) 31 a forming aside surface of the concave portion 31 on the first short side portion 3a side (first flange portion 32 a side) of the can body 3, a leadportion of an output terminal (hereinafter, referred to as a “negativeterminal”) 7 of a negative electrode and an output terminal(hereinafter, referred to as a “positive terminal”) 8 of a positiveelectrode are provided. In the battery 1 in the illustrated example, thebattery can 2 is on the positive electrode side. Therefore, the positiveterminal 8 is composed of one metal plate in an elliptical shape or aprismatic shape, attached to an outer surface of the upper wall portion31 a. Furthermore, as shown in a partially enlarged state in FIG. 4, thelead portion of a negative terminal 7 is composed of an attachment hole31 b passing through the upper wall portion 31 a, an insulating packing18 a made of resin placed outside of the upper wall portion 31 a, aninsulating packing 18 b made of rubber placed inside of the upper wallportion 31 a and a pressure plate 18 c, and the negative terminal 7fitted in the attachment hole 31 b through the insulating packing 18 a,18 b and the pressure plate 18 c, and by crimpling these componentssimultaneously to attach them to the upper wall portion 31 a, theattachment hole 31 b is sealed in an air-tight and liquid-tight state.One end surface of the negative terminal 7 is exposed to the outside ofthe can body 3, and the other end surface thereof is placed in theconcave portion 31, to which the conducting tab 6 led from thesheet-shaped negative electrode is connected.

The circumferential surface 31 c including the upper wall portion 31 aof the can body 3 forming a side surface of the concave portion 31 maybe formed so as to be orthogonal to the flange 32 and a bottom surface31 d of the concave portion 31. As shown in FIGS. 3 and 4, thecircumferential surface 31 c may be tilted so as to form a predeterminedobtuse angle (10° to 30°) with respect to the flange 32 and the bottomsurface 31 d of the concave portion 31. Because of this, a gap C formedbetween the inner surface of the can and the electrode body 5 at cornersof the battery can 2 is increased to some degree. Therefore, a spacethat can be used for storing an electrolyte solution is increased by theamount of the gap C, and consequently, an injection amount of theelectrolyte solution to the battery can 2 can be increased.

On the other hand, the metal cover 4 is composed of one metal plateobtained by press stamping, and the shape and size of its peripheraledge are set to be the same as those of an outer peripheral edge of theflange 32 in the can body 3. The metal cover 4 is bonded to beintegrated with the flange 32 of the can body 3, as shown in FIGS. 3 and4. The integrally bonded metal cover 4 seals the opening end of theconcave portion 31 of the can body 3, whereby the concave portion 31(battery case 2) is maintained in an air-tight and liquid-tight state.

The metal cover 4 can be bonded to be integrated with to the flange 32of the can body 3 by laser welding or heat adhesion using resin. In theformer case, under the condition that the flange 32 is aligned with themetal cover 4, laser welding is performed in vicinity of the peripheraledges thereof or over the entire outer circumferential portion P of theattached surfaces, whereby the metal cover 4 is bonded to be integratedwith the flange 32. Furthermore, in the latter case, the surface of theflange 32 or a peripheral edge portion 4 a of the metal cover 4 to beattached to the flange 32 is provided with resin as an adhesive, and theresin is melted temporarily with heat to thermally attach the flange 32to the metal cover 4, thereby bonding them to be integrated.

For example, as shown in an enlarged state in FIG. 4, a cut-in portion 4b to be a safety valve can be formed by press forming so as tocorrespond to a space S formed on one-end portion side-of the electrodebody 5 in the can body 3. The cut-in potion (safety valve) 4 b is brokenwhen a battery internal pressure is increased to a predeterminedpressure or more, thereby releasing the battery internal pressure tooutside.

In addition, in the battery 1, the metal cover 4 and one surface(surface forming the bottom surface 31 d of the concave portion) of thecan body 3 positioned so as to be opposed to the metal cover 4 areformed so as to have a slightly convex shape toward the inside of thebattery. The deformation amount in the projection direction of a centerof the convex portion is set to be in a range of 0.05 to 0.3 mm, wherebythe swelling of the battery can 2 in the thickness direction due to theexpansion of the electrode body 5 and an increase in a battery internalpressure are suppressed.

Next, the size, material, and the like of a battery and each constituentportion will be described.

A total thickness L3 of the battery 1 can be 3 mm or less, a length L4of the long side portion 3 c can be 65 mm or more, and a length L5 ofthe first short side portion 3 a (which also is applied to the secondshort side portion 3 b) can be 34 mm or more. In the battery in theillustrated example, L3=2.8 mm, L4=67 mm, and L5=35 mm. Although theentire shape of the battery in the illustrated example is prismatic, itmay have a disk shape or a circular shape.

For the battery can 2, i.e., the can body 3 and the metal cover 4, forexample, an iron plate, a nickel plate, an aluminum plate, an alloyplate of these metals, a magnesium alloy plate, a stainless steel plate,a rolled steel plate plated with nickel, a stainless steel plate platedwith nickel, and the like can be used. In the case of placing importanceon strength and light weight, it is preferable to use an aluminum alloyor a magnesium alloy having Hv (Vickers hardness) of 70 or more, whichhas high strength and light weight. Furthermore, in the case of placingimportance on resistance to corrosion with respect to an electrolytesolution, it is preferable to use a rolled steel plate or a stainlesssteel plate plated with nickel. Furthermore, regarding the metal cover4, the same material as that of the can body 3 is used on the bondedsurface side with respect to the can body 3, and a clad material forexample, nickel clad material obtained by stacking nickel) that is astacked material excellent in strength and lightness can be used on theopposite side surface.

The plate thickness of the can body 3 and the metal cover 4 can be setto be 0.2 mm or less, and more preferably about 0.15 mm. In theillustrated example, the plate thickness is 0.15 mm. In the battery 1 ofthe present invention, the can body 3 is formed by shallow drawing.Therefore, a hard material with high strength as described above can beused. As a result, even if the plate thickness is set to be small, theplate can sufficiently withstand the swelling of a battery.

In the case of thermal adhesion using resin, the thickness of a resinlayer after thermal fusion provided between the flange 32 and the metalcover 4 is set to be 0.1 mm or less so as to minimize the transmissionof moisture from outside, and preferably about 0.03 to 0.08 mm.Furthermore, the width of the resin layer corresponding to the widthdirection of the flange 32 is set to be 1 mm or more, and preferably 1.5mm or more. The width of the resin layer may exceed the width of theflange 32.

With the battery 1 as described above, the flange 32 of the can body 3bonded to be integrated with the metal cover 4 can be used forfacilitating an attachment/detachment operation with respect toequipment (not shown) (e.g., a portable information terminal) to bemounted in the battery 1. For example, a guide portion corresponding tothe flange 32 (in particular, the second flange portion 32 b positionedon the long side portion 3 c side of the can body 3) of the battery can2 is formed in a portion of the equipment where the battery 1 is to beattached, the flange 32 is inserted to the guide portion and allowed toslide therein, whereby an attachment/detachment with respect toequipment can be performed. Thus, a battery can be realized, which isexcellent in attachment to equipment, and can be easily separated fromthe equipment for disposal after use.

Furthermore, a flange width L1 of the first flange portion 32 a wherethe positive terminal 8 and the negative terminal 7 are provided is setto be 6 mm that is larger by 1 mm or more than a flange width L2 of thesecond flange portion 32 b. Therefore, as shown in FIGS. 5 and 6, aprotection circuit Q can be provided to the first flange portion 32 a,and the positive terminal 8 and the negative terminal 7 can beelectrically connected to the protection circuit Q at a shortestdistance. Thus, in the case of providing the protection circuit Q, it isnot necessary to separately keep a space and a base portion for theprotection circuit Q. In addition, wiring between the protection circuitQ and the respective terminals 8, 7 is made simplified.

In the flange 32 provided at the peripheral edge portion of the openingend of the can body 3, the metal cover 4 is bonded to the can body 3.Because of this configuration, for example, even in the case wherebonding is performed by laser welding, other components are isolated ata position relatively away from the welded portion. Therefore, thermalinfluence on various kinds of components constituting the battery 1,such as the insulating packings 18 a, 18 b, the electrode body 5, aseparator (not shown) can be avoided. Furthermore, in the case where themetal cover 4 is thermally bonded to the flange 32 via resin, a batterycan be produced at a lower cost compared with the case of using welding.

Furthermore, in the battery 1, a plate-shaped can body 3 obtained byshallow drawing is used, so that the battery can 2 with a thickness of 3mm or less can be formed relatively easily. In this case, there is noconstraint in terms of materials as in the case of using a deep-drawncan. Therefore, materials having required characteristics can beselected relatively freely from various materials as described above.Thus, a battery that can sufficiently withstand sticking, bending,swelling, and the like (in other words, that is excellent in resistanceto sticking, resistance to bending, resistance to swelling, and thelike) can be relatively easily obtained, although the entire thicknessis 3 mm or less.

Next, another exemplary configuration that can be adopted in attachingthe protection circuit Q to the battery 1 of the present invention willbe described.

FIG. 7 shows an example in which the positive terminal 8 and theprotection circuit Q are placed on the first flange portion 32 a of thebattery 1. The protection circuit Q shown in FIG. 7 is electricallyconnected to the negative terminal 7 provided on the upper wall portion31 a and the positive terminal 8 provided on the first flange portion 32a. Reference numeral 91 denotes a lead for electrically connecting theprotection circuit Q to the negative terminal 7. On an upper surface ofthe protection circuit Q, terminals 92, 93 are provided for externalconnection of a positive electrode and a negative electrode used forelectrically connecting the battery 1 to the external equipment (notshown). The points except for the above are the same or substantiallythe same as those in the above-mentioned example. Therefore, thecorresponding portions are denoted with the same reference numerals, andthe description thereof is omitted here (this also is applied to theexample described below).

With such a configuration, the protection circuit Q is attached to thefirst flange portion (wide flange portion) 32 a on which the negativeterminal 7 is provided. Therefore, the positive terminal 8 and thenegative terminal 7 can be electrically connected to the protectioncircuit Q at a shortest distance. Thus, in the case of providing theprotection circuit Q, it is not necessary to separately keep a space anda base portion therefor, and wiring between the protection circuit Q andthe respective terminals 8, 7 can be simplified.

FIG. 8 shows an example in which the positive terminal 8 and thenegative terminal 7 are provided on the first flange portion (wideflange portion) 32 a. In this example, when the protection circuit Q isattached to the first flange portion 32 a as shown in the figure, theprotection circuit Q is electrically connected to the negative terminal7 and the positive terminal 8 provided on the first flange portion 32 a.According to such a configuration, the protection circuit Q can beconnected to the positive terminal 8 and the negative terminal 7 in thebattery 1 more easily, and in addition, wiring between the protectioncircuit Q and the respective terminals 8, 7 can be simplified.

FIGS. 9 and 10 show an example in which the protection circuit Q ismodulized to be attached to the battery 1. In this example, theprotection circuit Q is incorporated to one surface (lower surface inthe illustrated example) of a substrate 100 to be modulized. On thesubstrate 100 constituting a protection circuit module 101, a pluralityof (3 in the illustrated example) elastic chips 102 are provided on anouter circumferential portion on a surface side where the protectioncircuit Q is incorporated, and engagement hooks 102 a are formedrespectively at ends of the elastic chips 102. On the other hand, at aperipheral edge portion of the first flange portion (wide flangeportion) 32 a of the battery 1, a rising portion 35 substantially in aU-shape in a plan view bent in the thickness direction of the batterycan 2 is provided, and engagement holes 35 a are formed at predeterminedpositions on a bottom side of the rising portion 35. As shown in FIG. 9,the protection circuit module 101 is fitted in the rising portion 35, soas to engage the engagement hooks 102 a of the protection circuit module101 with the engagement holes 35 a of the rising portion 35, whereby theprotection circuit module 101 is fixed to the first flange portion 32 a,as shown in FIG. 10.

With such a configuration, the protection circuit module 101 is fittedin the rising portion 35 provided on the first flange portion 32 a, andthe engagement hooks 102 a provided at the ends of the elastic chips 102are engaged with the engagement holes 35 a in the rising portion 35,whereby the protection circuit Q can be fixed easily to the first flangeportion 32 a. Furthermore, the protection circuit Q is not exposed tothe outside since it is modulized. Therefore, the protection circuit Qis prevented or suppressed from being damaged by mistake and dust isprevented or suppressed from adhering to the protection circuit Q.

FIGS. 11 and 12 show another example in which the protection circuit Qis modulized to be attached to the battery 1. In this example, thebattery can 2 constituting the battery 1 has a configuration in whichthe respective flange portions 32 are welded to each other under thecondition that opening sides of a pair of can bodies 3 are faced to eachother. In other words, in this example, one of a pair of can bodies 3 isused as a metal cover in the present invention, in place of the flatmetal cover 4 as shown in FIGS. 3 and 4. In the same way as in theabove-mentioned respective examples, the flange portions 32 faced toeach other are provided with the first flange portions (wide flangeportions) 32 a. However, in this example, cut-away portions 32 m areprovided at predetermined positions on both sides of the first flangeportion 32 a. On the other hand, the protection circuit Q isincorporated to be modulized in a resin molding 200 at least one surfaceof which is opened. At both side portions of the resin molding 200constituting a protection circuit module 201, a pair of elastic chips202 having hooks 202 a at ends are provided. On inner surface sides ofboth side portions of the resin molding 200, grooves 203, in which bothside portions of the first flange portions 32 a are fitted slidably, areformed. When both side portions of the first flange portions 32 a arefitted in the grooves 203 and slid to a predetermined position, thehooks 202 a of the protection circuit module 201 are engaged with thecut-away portions 32 m at the first flange portions 32 a as shown inFIG. 12, whereby the protection circuit module 201 is fixed to the firstflange portions 32 a.

With the above-mentioned configuration, both side portions of the firstflange portions 32 a are allowed to slide while being inserted to thegrooves 203 provided on both inner surfaces of the protection circuitmodule 201, whereby the hooks 202 a of the elastic chips 202 provided atboth side portions of the protection circuit module 201 are engaged withthe cut-away portions 32 m on both side portions of the first flangeportions 32 a. Thus, the protection circuit Q can be fixed to the firstflange portion 32 a easily. Furthermore, the protection circuit Q is notexposed to the outside since it is modulized. Therefore, the protectioncircuit Q can be prevented or suppressed from being damaged by mistakeand dust can be prevented or suppressed from adhering to the protectioncircuit Q.

FIGS. 13 and 14 show an example in which the protection circuit Q isattached to the first flange portion 32 a of the battery 1, theprotection circuit Q is covered with an aluminum case (coating) 300, andan peripheral edge on the lower end side of the case 300 is welded tothe first flange portion 32 a. On an upper surface of the aluminum case300, two holes 300 a are provided. The holes 300 a expose terminals 92,93 for external connection in the protection circuit Q to outside of thecase 300, when the protection circuit Q attached to the first flangeportion 32 a is covered with the case 300 as shown in FIG. 13.

With the above mentioned configuration, the protection circuit Qattached to the wide first flange portion 32 a is covered with thealuminum case 300, whereby the protection circuit Q is not exposed tothe outside. Thus, the protection circuit Q can be prevented from beingdamaged by mistake and dust can be prevented from adhering to theprotection circuit Q more exactly.

In the examples shown in FIGS. 7, 9, and the like, the terminals 92, 93for external connection of a positive electrode and a negative electrodeare provided on a predetermined surface (surface parallel to the flangeportion) in the protection circuit Q and the protection circuit module.However, as shown in FIG. 15, for example, only the terminal 93 forexternal connection of a negative electrode is provided on apredetermined surface in the protection circuit Q and the protectioncircuit module, and the terminal 93 for external connection of apositive electrode can be designed so as to be used also in the batterycan (positive can) 2. In this case, as shown in FIG. 15, if a pair ofupper and lower contacts RR are provided to external equipment, thebattery 1 is inserted between the contacts RR so as to bring one of thecontacts R into contact with the terminal 93 for external connection ofa negative electrode and to bring the other contact R into contact withthe battery can 2 that also functions as the terminal for externalconnection of a positive electrode, external equipment on which abattery is to be mounted can be electrically connected to the batteryeasily.

As described above, according to embodiments of the present invention, aplate-shaped shallow-drawn can is used for a can body constituting abattery can, and a flange portion to be bonded to be integrated with ametal cover is provided along a peripheral edge of the shallow-drawncan. Therefore, a thin battery can be realized, which is excellent inattachment to equipment for mounting the battery, and in which aprotection circuit can be mounted by simple wiring. In this case, if thecan body is bonded to be integrated with the metal cover with resin,integration by bonding can be simplified in the course of production,compared with integration by welding. This can reduce a production cost.

Furthermore, even in the case where the can body and the metal cover arebonded to each other by laser welding or the like, welding or the likecan be performed at a position relatively away from other componentmaterials. Therefore, thermal influence on various kinds of componentsconstituting a battery, such as an insulating packing, an electrode, anda separator can be avoided.

Furthermore, there is less constraint in terms of a material as in thecase of using a deep-drawn can, and a material having requiredcharacteristics can be relatively freely selected from variousmaterials. Therefore, a battery that is excellent in resistance tosticking, resistance to bending, resistance to swelling, and the likewhile having an entire thickness of 3 mm or less can be relativelyeasily obtained.

In the case where a part of the flange portion of the can body is formedto be wider, an output terminal of a positive electrode and/or anegative electrode or a lead portion thereof can be provided, and aprotection circuit can be attached to the wide flange portion.Therefore, the output terminal can be electrically connected to theprotection circuit at a shortest distance, which simplifies wiringtherebetween.

Furthermore, it is not necessary to separately keep a space and a basefor attaching a protection circuit, which is generally required forattaching the protection circuit to a thin battery. Furthermore, in thecase where a protection circuit is incorporated to be modulized in arequired component, in view of the attachment and the like to the wideflange portion, i.e., a predetermined protection circuit module is used,an attachment operation of the protection circuit to the battery can besimplified further. In addition, a protection circuit can be fixedexactly at a predetermined position, and simultaneously, can beelectrically connected to the output terminal easily.

While the invention has been described with respect to a limited numberof embodiments, those skilled in the art, having the benefit of thisdisclosure, will appreciate that other embodiments can be devised whichdo not depart from the scope of the invention as disclosed herein.Accordingly, the scope of the invention should be limited only by theattached claims.

1. A battery comprising: a can body having a concave portion foraccommodating an electrode body, formed by shallow drawing, and a flangeformed at a peripheral edge of an opening end; and a metal cover forsealing the opening end of the concave portion of the can body, whereinthe electrode body in which a positive electrode and a negativeelectrode are wound in a spiral shape with a separator interposedtherebetween, and a non-aqueous electrolyte solution in which anelectrolyte is dissolved in a non-aqueous solvent are accommodated inthe can body, and the can body is bonded to be integrated with the metalcover at the flange of the can body, whereby the electrode body and thenonaqueous electrolyte solution are sealed in the can body, the flangeis formed in a rectangular shape including four sides, and a flangeportion including one of the four sides is a wide flange portion formedso as to have a flange width larger than that of a flange portionincluding the remaining sides, a protection circuit is attached to thewide flange portion, and the protection circuit is incorporated to bemodulized in a substrate or a resin molding.
 2. The battery according toclaim 1, wherein the can body is bonded to be integrated with the metalcover by adhesion with resin.
 3. The battery according to claim 1,wherein the can body and the metal cover are composed of at least oneselected from the group consisting of an iron plate, a nickel plate, analuminum plate, an alloy plate thereof, a magnesium alloy plate, astainless steel plate, a rolled steel plate plated with nickel, and astainless steel plate plated with nickel.
 4. The battery according toclaim 1, wherein the metal cover and one surface of the can body placedso as to be opposed to the metal cover are formed respectively in aconvex shape toward an inside of the battery, and a deformation amountin a projection direction at a center of the convex shape is 0.05 to 0.3mm.
 5. The battery according to claim 1, wherein a part of the can bodyor a part of the metal cover opposed to the can body is provided with acut-in portion formed by press forming as a safety valve that releasesan internal pressure of the battery to outside when the internalpressure of the battery increases to a predetermined value or more. 6.The battery according to claim 1, further comprising an output terminalattached to the wide flange portion.
 7. The battery according to claim1, wherein among circumferential surface portions in a thicknessdirection of the can body forming side surfaces of the concave portion,a circumferential surface portion on a side where the wide flangeportion is positioned is provided with a lead portion of an outputterminal of one selected from a positive electrode and a negativeelectrode.
 8. The battery according to claim 1, wherein the protectioncircuit is incorporated to be modulized in a substrate provided with aplurality of elastic chips having engagement hooks at ends, atpredetermined positions on an outer peripheral portion, a peripheraledge of the wide flange portion to which the protection circuit moduleis to be attached is provided with a rising portion in a substantiallyU-shape in a plan view having engagement holes at predeterminedpositions, formed so as to be bent in a thickness direction of the canbody, and the engagement hooks of the elastic chips in the protectioncircuit module are engaged with the engagement holes in the risingportion, whereby the protection circuit module is fixed to the wideflange portion.
 9. The battery according to claim 1, wherein theprotection circuit is incorporated to be modulized in a resin moldingprovided with a pair of elastic chips having hooks at ends, at both sideportions, and having grooves in which the wide flange portion is fittedslidably on inner surface sides of the side portions, both the sideportions of the wide flange portion are provided with cut-away portionsat predetermined positions, and when both the side portions of the wideflange portion are fitted in the grooves in the protection circuitmodule to slide to a predetermined position, the hooks in the protectioncircuit module are engaged with the cut-away portions in the wide flangeportion.
 10. The battery according to claim 1, wherein the protectioncircuit is attached to the wide flange portion and an outside thereof iscovered with a metal case, and under this condition, the case is weldedto the wide flange portion.
 11. The battery according to claim 1,wherein among circumferential surface portions in a thickness directionof the can body forming side surfaces of the concave portion, acircumferential surface portion on a side where the wide flange portionis positioned is provided with a lead portion of a negative terminal ofa negative electrode, wherein one end surface of the negative terminalis exposed to an outside of the can body, and the other end surface ofthe negative terminal is in the concave portion of the can body andwherein the end surface of the negative terminal in the concave portionof the can body is connected to the negative electrode with a conductingtab.
 12. The battery according to claim 2, wherein the width of theresin exceeds the width of the flange.